Barr MC-1-0000 Adapter Plate Kit 3.0-Liter Engines. Converts older 3.0-Liter large intake port Exhaust Manifolds to the new 3.0 Liter high output small intake port cylinder heads. Use when repowering older 3.0-Liter engines with a newer 3.0-Liter vortec engine and you are using older exhaust manifold. Includes plate gaskets, and hardware for Mercruiser manifolds. Replaces OSCO MO4-HOK. Made in USA, 1-year limited warranty.